Ribbon shift assembly

ABSTRACT

A solenoid-operated actuating bail affords a positive, direct means to control shifting of the lift arms in a ribbon-lift guide or carrier assembly for a keyboard printer or typewriter in selecting a desired ribbon color or level for printing.

United States Patent [191 Becker June 26, 1973 RIBBON SHIFT ASSEMBLY [75] Inventor: Harold D. Becker, Riverton, Wyo.

[73] Assignee: Date] Corporation, McLean, Va.

[22] Filed:' Jan. 8, 1971 {211 App]. No.: 105,053

[52] US. Cl. 197/151, 197/156 [51] Int. Cl B41j 33/14 [58] Field ofSearch 197/151, 154, 156,

[56] References Cited UNITED STATES PATENTS 3/1963 Becker et a] 197/193/1965 ODaniel et a1 197/158 X 3,233,716 2/1966 Grashoff 197/1573,595,362 7/1971 Wolowitz... 197/157 2,919,784 l/1960 Morris 197/1593,154,185 10/1964 Kamp 197/156'X 3,349,888 10/1967 Page 197/151 XPrimary ExaminerRobert E. Pulfrey Assistant ExaminerR. T. RaderAttorney-Reilly & Lewis [57] ABSTRACT A solenoid-operated actuating bailaffords a positive, direct means to control shifting of the lift arms ina ribbon-lift guide or carrier assembly for a keyboard printer ortypewriter in selecting a desired ribbon color or level for printing.

3 Claims, 4 Drawing Figures PAIENIE0Juu2s ms 3.741.364'

IN vE/v TOR HAROLD D. BECKER ATTORNEYS RIBBON SHIFT ASSEMBLY Thisinvention relates to keyboard printers and more particularly relates tonovel and improved means for shifting a ribbon lift assembly in akeyboard printer to present a selected color or ribbon level forprinting.

It is customary to provide in typewriters for a ribbon shift mechanismwhich will cause a given area of the ribbon to be raised into positionfor printing. For example, the ribbon may have different color sections,such as, upper and lower, red and black color sections extending thelength of the ribbon tape; and when threaded through the ribbon feedmechanism suitable means are provided in association with the ribbonfeed mechanism to shift either of the color sections into position forprinting.

In single element printing machines, such as, for example, the IBMSelectric I/O Keyboard Printer, the rib bon carrier assembly is shiftedby a magnet-controlled, flexible cable trained over a series of pulleysat opposite ends of the typewriter, and the cable controls actuation ofa ribbon lift arm assembly to set either desired color level forprinting. It is proposed in accordance with the present invention toprovide a more positive, direct means of actuation of the ribbon liftarm or guide assembly in place of the tape-pulley arrangement and whichcan be activated either manually or by code in a reliable, highlyefficient manner.

It is therefore an object of the present invention to provide for anovel and improved ribbon shift control mechanism for a keyboardprinter.

It is another object of the present invention to provide for asolenoid-operated ribbon shift control assembly to effect positivedirect shifting of the ribbon carrier mechanism to present a desiredcolor for printing and wherein the shift control assembly either can beactivated by the operator or by remote code control.

It is a further object of the present invention to provide a novel andimproved ribbon shift control mechanism which is highly simplified andreadily installed to control shifting of the ribbon on the keyboardprinter as the ribbon is fed through the printer to present a desiredcolor for typing.

The instant invention is best exemplified by describing its use incontrolling the ribbon shift assembly on the ribbon carrier of a singleelement printer machine, for example, the Selectric I/O Keyboard Printermanufactured by International Business Machines of Armonk, New York. Forexample, when the color ribbon; that is, a ribbon divided into twodifferent color levels along its length, is passed through guide slotsof a ribbon carrier the ribbon carrier is shiftable about a horizontalaxis between an upper and lower print position. Specifically in a singleelement print machine, all of the characters of the type font are on asingle printing head which is selectively tiltable and rotatable topresent a selected character for printing in response to depression of agiven key lever. In this form of typewriter, the print head is advancedwith respect to a stationary platen, and the ribbon carrier as well asthe shift mechanism is advanced with the print head. The color level orprint position of the ribbon selected for typing is determined by theextent of displacement of the shift mechanism, which is associated withthe ribbon carrier, about a horizontal axis when it is engaged in eachprint cycle by a ribbon lift cam. Specifically, a cam followerassociated with the lift arm assembly includes a pivotal latch member orkeeper which in one position will limit the displacement of the lift armassembly when the cam follower is engaged by the cam so as to cause theribbon to be shifted only a limited distance for printing along onecolor level; and in a second position will allow the cam follower to befreely movable under the influence of the cam to shift the ribbon forprinting along the second color level.

In accordance with the present invention, linkage is provided between asolenoid and the cam follower latch to effect a more positive directcontrol over movement of the latch to either of the desired positionsfor shifting of the ribbon and to that end, essentially comprises anactuating link arm operated off the armature of the solenoid to pivot abell crank which is keyed for rotation of an actuating bail. The bailhas an axially offset portion traversing the length of travel of theribbon carrier and a control line from the bail into the cam followerlatch so that when the bail is rotated it will retract the control lineto effect pivoting of the latch to one of the print positions; and whenthe solenoid is deenergized, the latch is spring-loaded to return to theother print position. Thus, through a minimum of working parts, theribbon shift mechanism can be positively controlled either manually orby electrical signals, the actuating means of the 'present inventionbeing further characterized by being readily installable on existingkeyboard printers and operable with a minimum of wear, adjustment ormaintenance necessary.

The above and other objects, advantages and features of the presentinvention will become more readily appreciated and understood from thefollowing detailed description of a preferred form of invention whentaken together with the accompanying drawings, in which:

FIG. 1 is a perspective view of a portion of a ribbon shift assemblyincorporating the actuating mechanism of the present invention.

FIG. 2 is a top plan view of the actuating mechanism shown in FIG. 1.

FIG. 3 is an end view thereof; and

FIG. 4 is an opposite end view thereof.

Referring in more detail to the drawings, there is shown by way ofillustrative example in FIG. 1 a conventional ribbon shift mechanismassembly designated 10 which is employed in the Selectric typewritermanufactured and sold by International Business Machines of Armonk, NewYork. In the conventional mechanism, the typewriter ribbon T is dividedinto red and black sections designated R and B, respectively, and theribbon is threaded through open, slotted supports 12 on opposite sidesof a ribbon-lift guide or carrier assembly 13. Ribbon lift arm 14 and 15extend forwardly from connection to the guide assembly, are supported attheir forward ends on a shaft 16, and are joined together at theirforward ends by a common bracket 17 which is spaced and located directlybeneath the shaft 16. An extension plate 18 is arranged for rearwardextension from the bracket 17 and has an upright support arm 19 whichserves to support a stud 20 which extends transversely of the lift arms14 and 15 in spaced parallel relation to the supporting shaft 16. Thestud 20 cooperates with ribbon-lift cam mechanism 22 to control verticalswinging movement of the lift arms and guide assembly 13 about the shaft16 to properly locate either the red or black ribbon sections in thepath of the type font for typing in a manner to be presently described.

a sleeve 56 for connection to the upper end of the follower latch 28.Specifically, the rearward extremity of the cable hasa hooked endportion58 which is inserted in on aperture at the upper end of the followerlatch and the cable is freely slidable within the sleeve 56 to 5 followmovement of the offset portion 52 of the shift bail. Here the sleeve 56is mounted by a suitable spring clip 60 to aflange 62 which is attachedto the bracket tioned intermediately 'between the lift arm 14 and the Tsupport arm 20 and attached to the forward end of the cam follower 26 bya suitable screw 29. The opposite rear end of the cam follower 26 isattached at 30 to a stationary frame, not shown, but which is disposedjust outwardly of the lift arm 14 and permanently attached to thetypewriter frame. It will be seen that thecam follower latch 28 isprovided with intersecting vertical and horizontal slots 32 and 33,respectively, with the horizontal slot extending rearwardly from theupper end of the vertical slot 32. The cam follower 26 is biasedrearwardly by return spring 34. In turn, the cam follower latch is freeto pivot independently of the cam follower 26 abutthe pivot 29 and isnormally biased in a rearward direction by a latch spring 68 affixed atoneend t0 bracket 17 and at its opposite end to a stationary support 69,a shown in. FIG. 2, so that the stud 20 is normally aligned with andinserted in the vertical slot 32. In this position, when the camfollower latch is engaged by the cam in each printing cycle to raise thecam follower 26 and follower latch 28 about the pivot point 30 the stud20 will move throughthe vertical slot and accordingly the followermechanism will pivot independently of the lift arm and guide assembly.As a result, the ribbon T will be lifted-only to present the blacksection B along the upper halfof the ribbon for typing. In accordancewith conventional practice, by drawing the cam follower latch forwardly,independently of the cam follower 26, about its lower pivot point 29,the stud 20 is positionedin the horizontal slot 33. In this secondposition, when the cam follower 26 and latch 28 are pushedup by the cam24 the stud 20 will be forced to rise with the latch thereby causing theextension plate 18 and attached lift arms 14 and to rise to an extentlifting the typewriter ribbon T into a raised position so that the lowerred section of the ribbon is aligned in the path of the print charactersfor typing. I

An important feature of the present invention resides in a novel andimproved mechanism for shifting the follower latch 28 to the forwardposition in order to lift the red section of the ribbon T into positionfor typing.

To this end, as best shown in FIGS. 2 to 4, a ribbon shift solenoid 40is mounted on a vertical plate 41 attached to typewriter frame 42, andwhen energized, the solenoid activates plunger 44 to draw link arm 45downwardly. The link arm 45 operates through clevis 46 which ispivotally connected to the plunger, and the op 17 at the forward ends ofthe lift arms 14 and 15. In this relation it will be apparent thatrotation of the shift bail 50in a direction away from the follower latchwill draw the cable forwardlywherebyto draw the follower latch 28forwardly and position the stud 20 in the upper hori zontal slot 33 ofthe follower latch. Normally, however,

the bell crank is spring-loaded by means of a return spring 64 to rotatethe bail in a direction toward the follower latch so that the cable 54will not resist biasing of the follower latch by its own latch spring 68rearwardly to normally position the stud inthe vertical slot In use, theribbon lift cam 24 will rotate one revolu- 7 tion in each printing cyclewhen a key lever is depressed on the typewriter so as to impart alifting mo- I writer section T for printing. Normally, when the shift.

solenoid 40 is not energized, as previously mentioned,

7 the follower latch 28 is urged by its latch spring to a rearwardposition causing the stud 20 to 'be freely slidable with respect to thelatch when the follower is lifted in accordance with the guide liftassembly and raised 7 only to a position to locate the black sectionofthe ribbon in the path of acharacter. However, when the solenoid isenergized either by depression of a key lever to close an electricalcircuit into the solenoid or by code control during automatic printing,the solenoid will activate the plunger to rotate thebell crank 48 andshift bail ina directioncausing the offset porand draw thefollower latch28 forwardly in position with the stud in the upper horizontal slot 33.Free dis 7 position of the follower latch is effected just prior tolifting of the follower in each cycle so that the lifting I motionimparted to the follower and its latch will cause posite end of theclevis is pivotally connected to the w free end of a bell crank 48 whichis located directly adjacent the bracket or plate 41 inwardly of theclevis and is keyed to the end of a ribbon shift bail 50. The bail 50 isin the form of a solid shaft or rod traversing the tion 52 of the bail50 and extends rearwardly through lifting of the lift arm and guideassembly throughthe greater distance necessaryto position the redsection of the ribbon in the path of the character. When the sole-.

noidis deenergized, theshift bail is returned to its originaldisposition under the urging of its return spring and the follower latchis also returned by the latch spring.

'From theforegoing, utilization of a rigid rod or shaft in combinationwith thecable affords more direct and positive control over actuation ofthe follow-er latch while eliminating use of complicated pulleyand cableor tape arrangements in present day use. a g

It is to be understood from the foregoingt'hat various modifications andchanges may be made in the construction and arrangementof elementscomprising the typewriter ribbon which is provided with upper and lowerprinting levels, means pivotally supporting said guide assembly forvertical movement to present a selected printing level on the ribbon fortyping, a cam, cam follower means responsive to movement of the cam ineach printing cycle to undergo vertical movement, an extension membercarried by the lift arms selectively engageable with the cam followermeans in a first position of the cam follower means to transmit up anddown movement of the cam follower means to the lift arms to establish afirst printing level of the ribbon and in a second position permittingfree independent movement of the cam follower means with respect to thelift arms to establish a second printing level on the ribbon, thecombination therewith comprising:

an elongated substantially rigid and rotatable shift bail traversingsubstantially the width of said typewriter and journaled for rotation atopposite ends on said support frame for extension across the typewriterin a direction perpendicular to the lift arms including an axiallyoffset portion between said opposite ends selectively movable in adirection normal to its length upon rotative movement of the shift bailso as to be rotated toward and away from the cam follower means inresponse to rotation of said bail in advancing the cam follower meansbetween the first and second positions,

a draw cable secured by connecting means to the axially offset portionand extending between the axially offset portion on said shift bail andthe cam follower means and operative to advance said cam follower meansto one of the first and second positions in response to actuation androtation of the axially offset portion of said shift bail toward the camfollower means and to advance said cam follower means to the other ofthe first and second positions in response to rotation of the axiallyoffset portion away from said cam follower means,

actuating means operatively connected to said shift bail and beingselectively activated for rotation of the axially offset portion aboutthe axis of said shift bail in advancing the axially offset portiontoward and away from said cam follower means, and

return means associated with said shift bail and operative to return thecam follower means to the other of the first and second positions whensaid actuating means is not activated.

2. In a typewriter according to claim 1, said actuating means defined bya solenoid including a plunger, and a bell crank keyed to one end ofsaid shift bail to effect rotation of said shift bail when said solenoidis energized to advance the offset portion on said shift bail in i adirection away from the cam follower means.

3. In a keyboard printer having a support frame, a ribbon-lift guideassembly for supporting a typing ribbon which is provided with upper andlower printing levels of different colors wherein said guide assemblyhas lift arms extending forwardly and pivotally supported for verticalmovement of said guide assembly to present a selected printing level onthe ribbon for typing, a rotatable cam member spaced beneath said guideassembly, a cam follower mechanism including a cam follower latch inwhich the cam follower mechanism is responsive to engagement by therotatable can in each printing cycle to cause the cam follower latch tobe lifted, an extension arm carried by the lift arms on said guideassembly including a stud inserted in horizontal and verticalintersecting slots on the cam follower latch, the latch being pivotal toa first position in which the stud is disposed'in the verticalintersecting slot so as to permit free, independent movement of thelatch with respect to the lift arms and position the ribbon at a firstprinting level and a second position in which the stud is disposed inthe horizontal lifting slot to transmit lifting movement of the latch tothe lift arms and guide assemblyso as to raise the typing ribbon to asecond printing level, the combination therewith comprising:

a shift bail extending the substantial width of the printer andincluding opposite end portions journaled for rotation on said supportframe and having a shift portion axially offset with respect to the endsof said bail and extending transversely of the direction of pivotalmovement of the cam follower latch,

draw cable means extending between the offset portion on said shift bailand the cam follower latch and operative to advance the cam followerlatch to the first position in response to rotation of said shift bail,

actuating means for selectively rotating said shift bail to pivot thecam follower latch to the first position, said actuating means includinga solenoid, a plunger operatively connected to the solenoid for axialmovement thereby, and a bell crank operatively connected to said plungerand keyed to one end of said shift bail to effect rotation of said shiftbail when said solenoid is energized to advance the offset portion onsaid shift bail to said first position, and

return means for returning said shift bail to the second position whensaid actuating means is not activated.

1. In a typewriter having a support frame, a ribbon-lift guide assembly including lift arms for supporting a typewriter ribbon which is provided with upper and lower printing levels, means pivotally supporting said guide assembly for vertical movement to present a selected printing level on the ribbon for typing, a cam, cam follower means responsive to movement of the cam in each printing cycle to undergo vertical movement, an extension member carried by the lift arms selectively engageable with the cam follower means in a first position of the cam follower means to transmit up and down movement of the cam follower means to the lift arms to establish a first printing level of the ribbon and in a second position permitting free independent movement of the cam follower means with respect to the lift arms to establish a second printing level on the ribbon, the combination therewith comprising: an elongated substantially rigid and rotatable shift bail traversing substantially the width of said typewriter and journaled for rotation at opposite ends on said support frame for extEnsion across the typewriter in a direction perpendicular to the lift arms including an axially offset portion between said opposite ends selectively movable in a direction normal to its length upon rotative movement of the shift bail so as to be rotated toward and away from the cam follower means in response to rotation of said bail in advancing the cam follower means between the first and second positions, a draw cable secured by connecting means to the axially offset portion and extending between the axially offset portion on said shift bail and the cam follower means and operative to advance said cam follower means to one of the first and second positions in response to actuation and rotation of the axially offset portion of said shift bail toward the cam follower means and to advance said cam follower means to the other of the first and second positions in response to rotation of the axially offset portion away from said cam follower means, actuating means operatively connected to said shift bail and being selectively activated for rotation of the axially offset portion about the axis of said shift bail in advancing the axially offset portion toward and away from said cam follower means, and return means associated with said shift bail and operative to return the cam follower means to the other of the first and second positions when said actuating means is not activated.
 2. In a typewriter according to claim 1, said actuating means defined by a solenoid including a plunger, and a bell crank keyed to one end of said shift bail to effect rotation of said shift bail when said solenoid is energized to advance the offset portion on said shift bail in a direction away from the cam follower means.
 3. In a keyboard printer having a support frame, a ribbon-lift guide assembly for supporting a typing ribbon which is provided with upper and lower printing levels of different colors wherein said guide assembly has lift arms extending forwardly and pivotally supported for vertical movement of said guide assembly to present a selected printing level on the ribbon for typing, a rotatable cam member spaced beneath said guide assembly, a cam follower mechanism including a cam follower latch in which the cam follower mechanism is responsive to engagement by the rotatable can in each printing cycle to cause the cam follower latch to be lifted, an extension arm carried by the lift arms on said guide assembly including a stud inserted in horizontal and vertical intersecting slots on the cam follower latch, the latch being pivotal to a first position in which the stud is disposed in the vertical intersecting slot so as to permit free, independent movement of the latch with respect to the lift arms and position the ribbon at a first printing level and a second position in which the stud is disposed in the horizontal lifting slot to transmit lifting movement of the latch to the lift arms and guide assembly so as to raise the typing ribbon to a second printing level, the combination therewith comprising: a shift bail extending the substantial width of the printer and including opposite end portions journaled for rotation on said support frame and having a shift portion axially offset with respect to the ends of said bail and extending transversely of the direction of pivotal movement of the cam follower latch, draw cable means extending between the offset portion on said shift bail and the cam follower latch and operative to advance the cam follower latch to the first position in response to rotation of said shift bail, actuating means for selectively rotating said shift bail to pivot the cam follower latch to the first position, said actuating means including a solenoid, a plunger operatively connected to the solenoid for axial movement thereby, and a bell crank operatively connected to said plunger and keyed to one end of said shift bail to effect rotation of said shift bail when said solenoid is energized to advance the offset portion on said shift bail to said first position, and return means for returning said shift bail to the second position when said actuating means is not activated. 